The present invention relates to an electric wrench for vehicle repair and more particularly pertains to an electric wrench carried along in a motor vehicle using power supply from the motor vehicle for changing tires by loosening and tightening the bolts and nuts that fasten the wheels of the motor vehicle or of other motor vehicles.
It is not uncommon for a driver to replace a flat tire urgently on a highway or at place where there is not a car repair shop nearby or when it is not possible to call for emergency car repair service. For a long time, manual wrenches have been used to loosen and tighten the bolts and nuts so as to replace flat tires, and it is time consuming and laborious. There are now power wrenches existing in the marketplace for ease of tire replacement. However, some existing power wrenches use compressed air and so their structure is complicated and their manufacturing cost is high. Some other existing wrenches are with simplified structure but the output torque is not high enough and reaction torque and angular force commonly arise.